This invention relates to hand tools generally and in particular, to a rivet nut setting tool.
A rivet nut is a term used to identify a type of blind fastener commonly used in the sheet metal industry. FIG. 1 shows a known rivet nut and FIG. 2 shows a known rivet nut after installation. The uncompressed rivet nut is in the shape of a cylinder with a flange at one end. The cylinder is threaded internally beginning at the non-flanged end. A non internally threaded compression area, fabricated from a deformable material, extends downward from the flange.
In use, the rivet nut is inserted through a pre-drilled hole in the sheet good until the flange prevents further passage. A threaded member, such as a rod or mandrel, is inserted through the flange to threadably engage the internal threads. An extracting force is applied to the threaded member, thereby causing the non-threaded compression area of the rivet nut to compress, forming a second flange on the opposite side of the sheet good, preventing removal of the rivet nut. Upon removal of the threaded member, the internal threads remain to accept a bolt or other threaded attachment.
A wide variety of blind fastener setting tools are known in the art. Some are very sophisticated and expensive, while other tools are very simple and inexpensive. Some, particularly those used in manufacturing operations, are wholly or semi automatic.
For example, U.S. Pat. No. 3,256,730 to Faull is directed to a device for forming an aperture in tubular stock. The device utilizes a wedged shaped sliding mechanism to extend a cutting tool to pierce the stock, and has the ability to vary both the size of the hole pierced in the tube stock and the size of the tube stock.
U.S. Pat. No. 3,396,572 to Godsey is directed to an angle attachment for a rivet gun. The device utilizes a wedge having an inclined surface in contact with a diagonal surface to alter the vector of force by 90 degrees when using a reciprocating rivet gun and bucking bar held against a rivet head to shape the rivet.
U.S. Pat. No. 5,329,694 to Sickels, et al. is directed to a method and apparatus to secure a self-attaching fastener, such as a pierce or clinch nut or stud to a metal wall of an enclosed structure, such as a tube, from inside the structure. An anvil assembly includes relatively movable parts having mating incline surfaces that are moved to expand or contract the anvil assembly. The body portion of a self-attaching fastener is inserted into an anvil pocket, the anvil is inserted into an enclosed structure, and the anvil is then expanded to locate or position the fastener adjacent to the inner surface of the wall of the enclosed structure. A die member then installs the nut in the wall, after which the anvil is contracted to remove the anvil from the structure. The die member installs the nut into the wall, piercing the wall of the enclosed structure and capturing the nut by deforming wall material of the enclosed structure into regions of the fastener that are designed to accept such deformed material. U.S. Pat. No. 3,933,019 to Underland, et al. is directed to a tool for installing an internally threaded tubular rivet. A pair of levers are pivotally connected together with one of the levers having a portion with a hole. A tubular anvil is received in the hole and secured to the lever. A rod extends axially through the anvil and is relatively movable with respect to the anvil. After threading a tubular rivet onto the rod, a relative movement between the two levers will affect a relative movement between the rod and the anvil, causing the deformation of the rivet material.
U.S. Pat. No. 4,425,782 to Todisco is directed to a tool for setting rivet nuts. The tool comprises a plurality of tubular handle powered pullers. One puller receives in its threaded bore a mandrel holder capable of readily receiving and holding a plurality of mandrels, each mandrel designed and sized to set a particular threaded rivet nut or rivet bolt. Utilizing the lever action of the handles, the handles are pressed towards one another to set the rivet.
U.S. Pat. No. 5,299,442 to Graham is directed to an apparatus for installing threaded rivet nuts. The apparatus comprises a frame and a carriage mounted slidably on the frame. The frame has a work support part and the carriage is equipped with a fastener, the threaded end of which extends through a hole in the work support part. A jack is situated between one member attached to the frame and another on the carriage. Extension of the jack moves the carriage on the frame to retract the fastener part way into the hole in the work support part. Tension springs serve to restore the carriage to its at rest position relative to the frame when the jack is not extended. A threaded rivet nut is threaded onto the fastener, the shank of the rivet nut is inserted through a hole in the work piece, and the jack is extended to collapse the rivet nut shank.
U.S. Pat. No. 3,861,185 to Maddox is directed to a hand tool for the upsetting of a threaded rivet nut. The tool has a stationary held body member with a smooth bore extending there through to receive an elongated longitudinal movable member. The elongated member has its opposite ends threaded with one end adapted to receive the threaded rivet nut for upsetting while the other threaded end receives a nut for rotation relative to the stationary held body member. Rotation of the nut causes an axial force which causes deformation of the threaded rivet nut material.
While the Faull, Godsey and Sickels et al. patents all disclose hand tool utilizing wedging mechanisms, none are suited for compressing rivet nuts. The Faull patent is used for piercing, the Godsey patent is used for hammering, and the Sickels et al. patent is used for inserting. Other similar hand tools utilize a wedge mechanism to transmit forces to a work piece in a direction substantially perpendicular to application of the force. However, none of the prior art are directed to compressing rivet nuts, rather, they are directed to utilizing the work principal for a different specific application.
The Underland, Todisco, Graham and Maddox patents are all directed to hand tools utilized in collapsing and setting threaded rivet nuts. None of those patents utilize a wedging mechanism. The Underland and Todisco patents both utilize the levering of a pair of handles to withdraw a rod effectuating the deformation of the rivet nut material. The Graham patent utilizes a jack mechanism, while the Maddox patent utilizes an in-line threading mechanism to create axial movement of a rod or shank to effectuate deformation of the rivet nut material.
Accordingly, there remains a need for improved methods and devices to apply rivet nut setting forces. The present invention fulfills this need, and further provides related advantages.
The present invention includes both the device and the method utilizing two wedge shaped halves to retract a stud used to deform rivet nut material, thereby setting the rivet nut.
The tool consists of two wedge shaped halves and a stud passing through both halves, extending to receive the threads of an uncompressed rivet nut. A slide screw controls the wedging action, causing the stud to retract. A stabilizing rod passing transversely through the bottom wedge is utilized to resist the rotational forces created during activation of the slide screw.
The slide screw allows the top wedge and bottom wedge to slidably relate to one another, allowing the stud to increasingly extend beyond the bottom wedge. The extended stud threads into a rivet nut which is then passed through a predrilled hole in the material to which the rivet nut is to be fastened. Upon activation, the slide screw causes the top wedge to slide along the bottom wedge. The wedging action decreases the length of the stud extending beyond the bottom piece, creating a withdrawal force that causes the compression area of the rivet nut to deform, setting the rivet nut in the material.
One advantage of the present invention is the ability to conveniently and inexpensively accommodate rivet nuts of differing internal thread size.
Another advantage of the present invention is the ability to quickly, simply, and inexpensively set a rivet nut.